Mobile telecommunications networks and the devices that utilize the resources of these networks have evolved during the past couple of decades into networks in which data communication, in contrast to voice communication, is the dominant type of communication. This is of course not least due to the very fast evolution of handheld user equipment, UE, that operate more or less as personal computers with multiple applications running concurrently and exchanging large amounts of packet switched data with each other and other entities connected to the Internet. In other words, with modern day UEs there is a need of being always connected to the network.
Work is going on in the standardizing bodies, such as the third generation partnership project, 3GPP, for improving the performance of UEs as well as other nodes in the networks. Many work items within 3GPP propose improvements that will help UEs in achieving higher bit rate, remain connected for longer periods of time by using shared resources while at the same time consume less battery energy. For example, in the field of work related to high speed packet access, HSPA, the operational states Enhanced Cell-FACH, Enhanced Cell-PCH, Common E-DCH (E-DCH in Cell-FACH) and further enhancements to Cell-FACH (Release 11 of the 3GPP technical specifications) are some of the features that help achieving this. An idea behind these improvements is that while the UE remains connected in the CELL FACH state, it supports higher data rate both in uplink and downlink and consumes less battery. Secondly, in the beginning of 3GPP standardization, Cell-FACH was supposed to be a transient state between idle and Cell-DCH, but it has evolved to be a stable state in which the UE can stay for long durations.
The features mentioned above are spread over various 3GPP releases starting from Release 6 up until Release 11. However, as the skilled person will realize, actual deployment of these features in the networks will be gradual. Typically, advanced HSPA features will be deployed initially in important urban locations called hotspots. That is, not all cells in a network will be deployed with these features at the same time and there will be partial deployment of these features, which will lead to a situation where cells will have different feature set support. For example, a cell serving an urban area may have many advanced features deployed while an adjacent cell serving a suburban area may not have all features deployed. In addition, different network vendors may have support for different features.
A drawback with such a situation is that a user being near a radio cell boundary, or at a location in the border of coverage area of network nodes, will see different levels of service depending on which cell he/she is connected to. Needless to say, this provides a bad user experience. Moreover, a user that experiences such a situation with different levels of service has no possibility to control selection of a “feature rich” cell even if such a cell is available at the location where the user is present.